Questions tagged [physical-organic-chemistry]
For questions about how organic molecules and reactions are investigated using physical experiments.
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Vapors of Aqueous solutions
I'm dealing with a common photoresist developer TMAH (tetramethylammonium hydroxide) and attempting to design a vapor sensor for a sealed chamber. Now I havent been able to confirm what exactly is ...
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Overlap integrals in Hückel theory
In Hückel theory we are only interested in π systems, where $\mathrm p_z$ orbitals overlap. One of the approximations in Hückel theory is that the overlapping $\mathrm p_z$ orbitals are orthonormal:
$...
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How do we obtain the π molecular orbitals for allene via Hückel theory?
For a conjugated system, for instance 1,3-butadiene, we can try to obtain the π molecular orbital energies and wavefunctions via Hückel theory. In our given molecule, there are 4 interacting Pz ...
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A question about potential difference across a membrane
Membrane potential of living cells arising from the difference of concentration of ions on both sides of the membrane, but why didn't someone use selective polymers as AEM (Anion Exchange Membrane) ...
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What exchange timescales are needed to cause decoupling in NMR?
I'll try to explain the source of my confusion as clear as possible:
(*) The methyl protons in toluene are decoupled because the C-C bond between the methyl group and benzene allows very fast ...
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Why does Larmor precession occur in NMR?
Larmor precession is the phenomenon that in NMR the spin (and by default also the magnetic dipole moment) of protons does not line up with the applied magnetic field but rather precesses around this ...
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What is the justification for using the Marcus rate equation to model charge transport in organic semiconductors?
I am trying to understand the history of how Marcus theory moved from describing electron exchange reactions in aqueous ionic solutions to also being applied to describe transport in organic ...
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What can we say about the dipole moment of terephthalic acid?
The dipole moment of quinol is not zero because it can exist in two different energetically favourable conformations. The weighted average is calculated to arrive a dipole moment of 1.6 D.
According ...
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Why does the dipole moment of molecules go from positive to negative? [duplicate]
In physics the dipole moment is said to go from the negative to the positive pole, check for instance https://en.wikipedia.org/wiki/Electric_dipole_moment (Elementary definition).
This makes sense ...
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Ratio of uncharged to charged side chains [closed]
The $\mathrm{p}K_\mathrm{a}$ of the side chain imidazole group of histidine is $6.0.$ What is the ratio of uncharged to charged side chains at $\mathrm{pH}~7?$
Here's my attempt to the solution:
$$7 ...
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Volatility comparison for isomers of phthalic acid
All the atoms of these compounds are in a plane.
o-phthalic acid can show extensive intra-molecular hydrogen bonding as well as inter-molecular hydrogen bonding.
m-phthalic acid can show intra-...
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Enantiomeric excess catalysed
Enantiomeric excess is defined as
$$ee = \frac{[R]-[S]}{[R]+[S]}$$
I found this problem in an IChO paper:
"When using the enantiomerically pure (BINOL)Al(OiPr) as a catalyst for reduction of ...
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Why has nature evolved to put a porphyrin (i.e. chlorophyll) as the chromophore in a leaf? [closed]
I'm stumped by this question:
Why has nature evolved to put a porphyrin (i.e. chlorophyll) as the chromophore in a leaf?
I've thought that it might have something to do with how sun emits light ...
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Enzyme Kinetics
How come enzymes with a lower $K_\mathrm{m}$ are more easily saturated with substrate than an enzyme with higher $K_\mathrm{m}?$
Is it because enzymes with higher $K_\mathrm{m}$ are able to bind ...
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Why does the reduction of Dichromate to Chromium 2 need an acid? [closed]
The Ecell shows that Zn is enough. Then why, are both of them required?
Also, can I use any acid ? Or only HCl + H2SO4
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